When you subscribe to a calendar you are offered the choice of importing it as a new calendar - in which case it will appear in the list - or adding it to an existing calendar. It sounds as if this is what you have done: do the events in this calendar appear in the same colour as another calendar?
If this is what you have done you have inextricably merged the calendars. You can only delete the unwanted events one at a time.
Thanks for your reply. I "subscribed" to a couple of motorsports calendars in iCal by visiting a direct link on the Apple website like this one: http://www.apple.com/downloads/macosx/calendars/2011motogpworldchampionshipcalen darprovisional_gpticketltd.html
This adds the events contained in this calendar directly to iCal and I can't for the life of me find a way to "unsubscribe" or eliminate these entries short of erasing them manually one by one. Unfortunately, there are many of them.
If you know how I may go about doing this in an efficient manner, please let me know!